Maybe hank has a whole team, Janet Van Dyne, Scott Lang, and Bill Foster too. So that Pym not only has Janet, but a group of friends and supporting cast. Then in later films they become bigger characters. Just like Rhodey in Iron Man 1 and 2 and then 3. Scott becomes the next Ant Man, and Bill becomes the next Goliath/Giant Man.

This makes some sense. I think we like seeing our heroes have a bunch of friends. Makes them likable.

Stark, Rhodey, Pepper, Happy, J.A.R.V.I.S.
Thor, Sif and the Warriors Three
Captain America, Bucky, and the rest of the Howling Commandos
The AVENGERS :P